1) Field of the Invention
The present invention relates to a microprocessor having a processor core.
2) Description of the Related Art
In recent years, a method of incorporating a debugger interface in a microprocessor, connecting the debugger interface to a debugger, thereby analyzing the state within the processor, and facilitating debugging at the time of software development is known.
By using this method, it is possible to access resources such as registers or memories in the processor from the debugger via the debugger interface incorporated in the processor. There is an advantage that, for example, step execution of a program operating in the processor can be performed.
By incorporating the debugger interface, it becomes easy for a software developer to verify the operation of the program. On the other hand, however, there is a problem that it becomes easy for other software developers and users to analyze the software.
For example, if developed software contains secret information, it is necessary to prevent software users from analyzing the software. In addition, it is also necessary to prevent other software developers from analyzing the software.
As a technique for that purpose, a method of prohibiting the debugging function based on a key selected at the time of decoding, and a method of prohibiting the operation of the debugging function when a program of protection subject stored in a memory within the processor is selected as a debugging subject are proposed (for example, see Japanese Patent Application Laid-Open No. 2002-244757).
If debugging for a predetermined program or the like is prohibited, however, debugging for that program cannot be executed at all, resulting in inconvenience. It is desired to improve the debugging function by controlling whether to enable the debugging function more suitably.